While long-term isolation can even make adultslose their minds, its effects on young people can be particularly wrenching.

Prisons and jails across America keep inmates under the age of 18 in solitary confinement, according to a report last year from Human Rights Watch and the ACLU. That means typically 22 hours a day in total isolation, behind a steel door. The confinement can last months.

Many vulnerable young people start to turn on themselves when they’re left all alone.

“You’re left with your thoughts and all the time in the world,” former teenage prisoner James Burns, now 26, told Business Insider. “You think of everything in the world you can think of. After a certain amount of time, it doesn’t take long for you to start punishing yourself.”

Burns, whose life inspired the film “Jamesy Boy,” was living on the streets of Denver as a young teen when he got involved with older guys who robbed drug dealers. It was the robbery of a coffee shop, though, that sent him to Colorado’s Youthful Offender System (YLS) when he was about 15.

Burns spent 4 years at YLS and says he had roughly 10 stints in solitary — the longest of which lasted 9 months. He tormented himself in solitary and lost hope. “You begin to turn on yourself … I felt like I was a piece of shit,” he said. “I never felt like I was ever going to be free again.” He kept thinking about his bad decisions, he said.

Other young people feel totally hopeless when they’ve been isolated, according to the ACLU and Human Rights Watch report.

“[I felt] doomed, like I was being banished … like you have the plague, or you are the worst thing on earth. Like you are set apart [from] everything else,” a teen identified only as Molly J. told Human Rights Watch.

For Burns, it wasn’t much of a relief when he got out of solitary. “When you leave solitary, even going back into the general population, you feel like an outcast among outcasts,” Burns said.

A New Jersey corrections officer union called PBA Local 105 has argued that “restricted engagement” is necessary to punish bad behaviour such as the brutal attack of a corrections officer. “The truth is that it places violent juveniles away from the inmate population as they ponder the behaviour that placed them in this position,” Union President Lance Lopez said in a statement.

Sadly for teenage inmates, though, all of that time to think about what they’ve done might do more harm than good.